Disable base/logging.h stderr logs by default for webrtc/ tests.

base/logging.h dumped to stderr by default in debug mode, but webrtc
"trace" (via system_wrappers/../logging.h) has that feature disabled by
default. This makes the two consistent.

Bonus: log the filename:line in base/logging.h, which exists in the
system_wrappers variant.

TEST=neteq_impl.cc logs (which use base/logging.h) no longer appear in
debug mode, unless --logs=true is passed. Filenames appear correctly.

Review URL: https://codereview.webrtc.org/1331503002

Cr-Commit-Position: refs/heads/master@{#9868}
4 files changed